[RamAirIV28]

Originally Posted by Bruce Meyer

Contrary to what others have posted, you must back off the bolt to properly re-torque them. What you have to do is one at a time. Back it off a 1/2 turn and then torque to 100 ft lbs in one motion. If you just try to torque them when they are tight, the breakaway torque is much more than the actual torque value. It wont be accurate.

I agree, back them off and then re torque

Actually I torque initially to the low end of the range run it up to brake in the cam and check every thing, once I feel its all good I loosen up the head bolts , then retorque to the top end of the range.

run it up again and check for everything

then I do the block seal routine

[lust4speed]

Some light reading material:

Flatout Gasket Tips

Felpro Tech Tips

Dragracing On Line Forum

Yellow Bullet Forum

Wiki Answers

You'll notice the first two links are gasket manufacturer's tech tips - and one would suspect that they will have at least a partial handle on what works.

[gtofreek]

Originally Posted by Lee

Jeff, I never retorque head gasket either. Maybe with copper head gaskets, or other "non-normal" situations it is required, but not on street-strip motors using normal gaskets.

But, if you torque all the head bolts to 95, then "retorque" them to 100, you will find many of them do not move at all. Does that mean they were already "100"? No, it means the static CoF is higher than 5lb-ft for those. The ONLY way to get them 100 (from 95) is to back them off SLIGHTLY, then re-torque to 100.

I DO NOT make a practice of doing this myself, but I've seen it mentioned several times in my life.

At least you and Bruce and a couple others get it. When I torque head bolts, I leave at least 25 Lbs. to the last torque setting. If I try to do it with just 10-15 lbs. It won't move the bolt at all before the wrench clicks off. The only thing the OP will find out by just setting the wrench to 100 lbs. and checking them is if some of them were never torqued to 100 in the first place. Then, that would be the fault of whoever put the heads on.

[tpssonic]

When I torque head bolts, I leave at least 25 Lbs. to the last torque setting. If I try to do it with just 10-15 lbs. It won't move the bolt at all before the wrench clicks off.

Very true. This is due to the coefficient of static friction being greater than the coefficient of sliding friction. After all, bolt threads are merely a glorified incline plane in the form of a helix/spiral. Slide just about anything across a surface (e.g. furniture across the floor) and you will note it typically takes a measurable additional amount of effort to get it moving initially...once it is in motion, it takes less force to keep it moving.

The only thing the OP will find out by just setting the wrench to 100 lbs. and checking them is if some of them were never torqued to 100 in the first place.

Not necessarily true. If you just torque it to 100 ft/ lbs. from the get-go (and are sure it is 100 ft/lbs.) torquing of the rest of the bolts may pull the head in more, effectively lowering the actual finished torque of that first-tightened bolt(s), even though it WAS 100 ft. lbs. to start with. The latter bolts will be at, or near the 100 ft/lbs., the but the earlier one(s) may not be anymore. The more "give" in the head and the more bolts the head had engineered to provide the needed clamping force for the application, the more this is true.

Always torque the heads in proper sequence and in proper increments as Paul has described above.

That being said and the proper torque sequence performed (assuming the threads were clean and not galled), I vote for the bolts being too long. I would verify that they are not too long before putting additional twist on "bottomed out" bolts" for fear of damaging the threads. More often than not, additional tightening will stop the leak. However you must ask yourself, "Are you feeling lucky, punk?"

Tony

[lust4speed]

A little late, but here are pics of the black Felpro gaskets that wouldn't seal up because of the extra thick compression ring. Knew I had them somewhere. The gasket had been torqued down and installed properly and we had coolant leaking out on the floor. The pics are of the compressed gasket after it was removed from the engine. Even the composite part of the gasket was thicker than normal.

[Rocky Rotella]

Did FASTGOAT66 ever mention if he's using stock or ARP head bolts, and to what spec either was torqued?

I recall seeing something similar occur with ARP head bolts if lubed with 30W oil and 95 to 100ft/lbs. Simply not enough clamping force to keep the engine sealed up tight while the components expand and contract from ambient temperature changes.

[FASTGOAT66]

The machine shop used my stock head bolts with oil. what ever stock specs were is what they did. It makes sence after a few heat cycles to retorque the head bolts. I just never did. Im going to get a torque wrench on each bolt and get back with my findings. Thank all you guys for taking the time to help me.

[i82much]

I think the answers regarding the differences in friction coefficients are correct. think of sliding a piece of furniture across the floor - hard to get started, easy to keep it moving.

[pugslyx234]

Hope for the best expect the worst good Ruck.

[chiphead]

My 1966 Motors Repair Manual says head bolt torque is 95 ft-lbs for '59-66 engines.
I've always had good luck with Felpro 1016 gaskets, even on engines with stock or pitted deck surfaces.